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NK-33

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NK-33
The Russian NK-33 was modified and renamed the AJ26-58 by Aerojet. This AJ26-58 is shown on the test stand at John C. Stennis Space Center.
Country of originSoviet Union
Date1970s
DesignerKuznetsov Design Bureau
ManufacturerJSC Kuznetsov (Mashinostroitel)
Application1st/2nd-stage engine
Associated LV
PredecessorNK-15, NK-15V
SuccessorAJ26-58, AJ26-59, AJ26-62
Liquid-fuel engine
PropellantLOX / RP-1
CycleStaged combustion
PumpsTurbopump
Performance
Thrust, vacuum1,680 kN (380,000 lbf)
Thrust, sea-level1,510 kN (340,000 lbf)
Throttle range50–105%
Thrust-to-weight ratio137
Chamber pressure14.83 MPa (2,151 psi)
Specific impulse, vacuum331 s (3.25 km/s)
Specific impulse, sea-level297 s (2.91 km/s)
Dimensions
Length3.7 m (12 ft)
Diameter2 m (6 ft 7 in)
Dry mass1,240 kg (2,730 lb)
References
References[1]

The NK-33 and NK-43 are rocket engines designed and built in the late 1960s and early 1970s by the Kuznetsov Design Bureau. The NK designation is derived from the initials of chief designer Nikolay Kuznetsov. The NK-33 was among the most powerful LOX/RP-1 rocket engines when it was built, with a high specific impulse and low structural mass. They were intended for the ill-fated Soviet N1F Moon rocket, which was an upgraded version of the N1. The NK-33A rocket engine is now used on the first stage of the Soyuz-2-1v launch vehicle. When the supply of the NK-33 engines are exhausted, Russia will supply the new RD-193 rocket engine. It used to be the first stage engines of the Antares 100 rocket series, although those engines are rebranded the AJ-26 and the newer Antares 200 and Antares 200+ rocket series uses the RD-181 for the first stage engines, which is a modified RD-191, but shares some properties like a single combustion chamber unlike the two combustion chambers used in the RD-180 of the Atlas V and the four combustion chambers used in the RD-170 of the Energia and Zenit rocket families, and the RD-107, RD-108, RD-117, and RD-118 rocket engines used on all of the variants of the Soyuz rocket.

Design

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Simplified diagram of NK33 rocket engine

The NK-33 series engines are high-pressure, regeneratively cooled oxygen-rich staged combustion cycle bipropellant rocket engines. The turbopumps require subcooled liquid oxygen (LOX) to cool the bearings.[2] The United States had not investigated oxygen-rich combustion technologies until the Integrated Powerhead Demonstrator project in the early 2000s.[3] The Soviets, however, perfected this method.

The problem is that hot high-pressure oxygen must flow throughout the engine. If the surfaces contacting this oxygen were bare metal, they would corrode too quickly. The problem was solved using an inert enamel coating on all metal surfaces in contact with the hot oxygen.[4]

The NK-33 engine has among the highest thrust-to-weight ratio of any Earth-launchable rocket engine; only the NPO Energomash RD-253, SpaceX Merlin 1D, and SpaceX Raptor engines achieve a higher ratio. The NK-43 is similar to the NK-33, but is designed for an upper stage, not a first stage. It has a longer nozzle, optimized for operation at altitude, where there is little to no ambient air pressure. This gives it a higher thrust and specific impulse, but makes it longer and heavier. It has a thrust-to-weight ratio of about 120:1.[5]

The predecessors of NK-33 and NK-43 are the earlier NK-15 and NK-15V engines respectively.

The oxygen-rich technology lives on in the RD-170/-171 engines, their RD-180, and recently developed RD-191 derivatives, but these engines have no direct connection to the NK-33 except for the oxygen-rich staged combustion cycle technology, the kerosene/RP-1 fuel, and in case of the RD-191 and its variants like the RD-193 and the RD-181, the single combustion chamber instead of the multiple chambers in previous Russian rocket engines.

History

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N-1

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The N-1 launcher originally used NK-15 engines for its first stage and a high-altitude modification (NK-15V) in its second stage. After four consecutive launch failures and no successes, the project was cancelled. While other aspects of the vehicle were being modified or redesigned, Kuznetsov improved his contributions into the NK-33 and NK-43 respectively.[6] The 2nd-generation vehicle was to be called the N-1F. By this point the Moon race was long lost, and the Soviet space program was looking to the Energia as its heavy launcher. No N-1F ever reached the launch pad.[7]

When the N-1 program was shut down, all work on the project was ordered destroyed. A bureaucrat instead took the engines, worth millions of dollars each, and stored them in a warehouse. Word of the engines eventually spread to the US. Nearly 30 years after they were built, rocket engineers were led to the warehouse. One of the engines was later taken to the US, and the precise specification of the engine was demonstrated on a test stand.[7]

Combustion-chamber design

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The NK-33 oxygen-rich closed-cycle technology works by sending the auxiliary engines' exhaust into the main combustion chamber. The fully heated liquid O2 flows through the pre-burner and into the main chamber in this design. The extremely hot oxygen-rich mixture made the engine dangerous: it was known to melt 3-inch (76 mm) thick castings "like candle wax[citation needed]. Oxidizer-rich staged combustion had been considered by American engineers, but was not considered a feasible direction because of resources they assumed the design would require to make work.[8] One of the controversies in the Kremlin over supplying the engine to the US was that the design of the engine was similar to Russian ICBM engine design. The NK-33's design was used in the later RD-180 engine, which had twice the size of the NK-33. The RD-180 engines were used (as of 2016) to power the Atlas V rocket. This company also acquired a license for the production of new engines.[9][10][11]

Sale of engines to Aerojet

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About 60 engines survived in the "Forest of Engines", as described by engineers on a trip to the warehouse. In the mid-1990s, Russia sold 36 engines to Aerojet General for $1.1 million each, shipping them to the company facility in Sacramento CA.[12] During the engine test in Sacramento, the engine hit its specifications.

Aerojet has modified and renamed the updated NK-33 to AJ26-58, AJ-26-59 and AJ26-62, and NK-43 to AJ26-60.[9][10][11][13]

Kistler K-1

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Kistler Aerospace, later called Rocketplane Kistler (RpK), designed their K-1 rocket around three NK-33s and an NK-43. On 18 August 2006, NASA announced that RpK had been chosen to develop Commercial Orbital Transportation Services for the International Space Station. The plan called for demonstration flights between 2008 and 2010. RpK would have received up to $207 million if they met all NASA milestones,[14][15][16] but on 7 September 2007, NASA issued a default letter, warning that it would terminate the COTS agreement with Rocketplane Kistler in 30 days because RpK had not met several contract milestones.[17]

Antares

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An Antares rocket being rolled out for testing, showing the two NK-33 engines

The initial version of the Orbital Sciences Antares light-to-medium-lift launcher had two modified NK-33 in the first stage, a solid Castor 30-based second stage and an optional solid or hypergolic third stage.[18] The NK-33s were imported from Russia to the United States, modified, and re-designated as Aerojet AJ26s. This involved removing some electrical harnessing, adding U.S. electronics, qualifying it for U.S. propellants, and modifying the steering system.[19]

In 2010 stockpiled NK-33 engines were successfully tested for use by the Orbital Sciences Antares light-to-medium-lift launcher.[19] The Antares rocket was successfully launched from NASA's Wallops Flight Facility on 21 April 2013. This marked the first successful launch of the NK-33 heritage engines built in early 1970s.[20]

Aerojet agreed to recondition sufficient NK-33s to serve Orbital's 16-flight NASA Commercial Resupply Services contract. Beyond that, it had a stockpile of 23 1960s- and 1970s-era engines. Kuznetsov no longer manufactures the engines, so Orbital sought to buy RD-180 engines. Because NPO Energomash's contract with United Launch Alliance prevented this, Orbital sued ULA, alleging anti-trust violations.[21] Aerojet offered to work with Kuznetsov to restart production of new NK-33 engines, to assure Orbital of an ongoing supply.[22] However, manufacturing defects in the engine's liquid-oxygen turbopump and design flaws in the hydraulic balance assembly and thrust bearings were proposed as two possible causes of the 2014 Antares launch failure.[23] As announced on 5 November 2014, Orbital decided to drop the AJ-26 first stage from the Antares and source an alternative engine. On 17 December 2014, Orbital Sciences announced that it would use the NPO Energomash RD-181 on second-generation Antares launch vehicles and had contracted directly with NPO Energomash for up to 60 RD-181 engines. Two engines are used on the first stage of the Antares 100-series.[24]

Current and proposed uses

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RSC Energia is proposing an "Aurora-L.SK" launch vehicle, which would use an NK-33 to power the first stage and a Blok DM-SL for the second stage.[25]

Soyuz-2-1v

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In the early 2010s the Soyuz launch vehicle family was retrofitted with the NK-33 engine – using the lower weight and greater efficiency to increase payload; the simpler design and use of surplus hardware might actually reduce cost.[26] TsSKB-Progress uses the NK-33 as the first-stage engine of the lightweight version of the Soyuz rocket family, the Soyuz-2-1v.[27] The NK-33A intended for the Soyuz-2-1v was successfully hot-fired on 15 January 2013,[28] following a series of cold-fire and systems tests of the fully assembled Soyuz-1 in 2011–2012.[29] The NK-33 powered rocket was finally designated Soyuz-2-1v, with its maiden flight having taken place on 28 December 2013. One NK-33 engine replaces the Soyuz's central RD-108, with the four boosters of the first stage omitted. A version of the Soyuz rocket with four boosters powered by NK-33 engines (with one engine per booster) has not been built, which results in a reduced payload compared to the Soyuz-2 launch vehicle.

Versions

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During the years there have been many versions of this engine:

  • NK-15 (GRAU index 11D51): Initial version for the N1 first stage.
  • NK-15V (GRAU index 11D52): Optimized for vacuum operation, used on the N1 second stage.
  • NK-33 (GRAU index 11D111): Improved version of NK-15 for the N1F first stage, never flown.
  • NK-43 (GRAU index 11D112): Improved version of NK-15V optimized for vacuum operation, used on the N1F second stage, never flown.
  • AJ26-58: NK-33 modified by Aerojet Rocketdyne. Planned to be used on the Kistler K-1, but the project was cancelled and the engine was never flown.
  • AJ26-59: NK-33 modified by Aerojet Rocketdyne. Planned to be used on the Kistler K-1, but the project was cancelled and the engine was never flown.
  • AJ26-62: NK-33 modified by Aerojet Rocketdyne with additional gimbal mechanism. Used on the Antares 100-series first stage.
  • NK-33A (GRAU index 14D15): Refurbished NK-33 used on the Soyuz-2.1v first stage.
  • NK-33-1: Uprated NK-33 with gimbal mechanism. Planned to be used on the future Soyuz-2.3 core stage.
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See also

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References

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  1. ^ "LRE NC-33 (11D111) and NC-43 (11D112)" (in Russian). Retrieved 1 April 2015.
  2. ^ "Orbital ATK ready for Antares' second life". NASASpaceflight. 21 January 2016. Retrieved 18 March 2016.
  3. ^ U.S. Air Force-NASA Technology Demonstrator Engine for Future Launch Vehicles Successfully Fired During Initial Full Duration Test.
  4. ^ Reusable Booster System: Review and Assessment. National Academic Press. January 2013. p. 29. Retrieved 23 July 2024.
  5. ^ Astronautix NK-43 entry Archived 28 October 2007 at the Wayback Machine
  6. ^ Lindroos, Marcus. The Soviet Manned Lunar Program Massachusetts Institute of Technology. Accessed: 4 October 2011.
  7. ^ a b Clifton, Dan (1 March 2001). "The Engines That Came in from the Cold". Channel 4. London. Ideal World Productions. Retrieved 3 January 2014.
  8. ^ Cosmodrome History Channel, interviews with Aerojet and Kuznetsov engineers about the history of staged combustion
  9. ^ a b "Space Lift Propulsion". Aerojet. April 2011. Archived from the original on 14 August 2011.
  10. ^ a b Clark, Stephen (19 December 2010). "Taurus 2 main engine passes gimbal steering test". Spaceflight Now. Tonbridge, Kent, UK. Archived from the original on 29 October 2013. Retrieved 3 January 2014.
  11. ^ a b "NK-33". Mark Wade (Encyclopedia Astronautica). Archived from the original on 25 June 2002. Retrieved 25 March 2006.
  12. ^ "Space Propulsion | Development of U.S. Closed-loop Kerolox Engine Stuck in 2nd Gear - SpaceNews.com". 12 July 2013. Retrieved 17 September 2016.
  13. ^ "MODIFICATION AND VERIFICATION TESTING OF A RUSSIAN NK-33 ROCKET ENGINE FOR REUSABLE AND RESTARTABLE APPLICATIONS" (PDF). Aerojet and N.D. Kuznetsov SSTC. Archived (PDF) from the original on 9 March 2019. Retrieved 17 August 2020.
  14. ^ "NASA selects crew, cargo launch partners". Spaceflight Now. 18 August 2006.
  15. ^ "NASA Selects Crew and Cargo Transportation to Orbit Partners". SpaceRef. 18 August 2006. Archived from the original on 26 May 2012.
  16. ^ Alan Boyle (18 August 2006). "SpaceX, Rocketplane win spaceship contest". NBC News. Archived from the original on 4 November 2013.
  17. ^ "RpK's COTS Contract Terminated" (Press release). Aviation Week. 10 September 2007. Archived from the original on 12 May 2011. Retrieved 10 September 2007.
  18. ^ "Antares" (PDF). Orbital.
  19. ^ a b Clark, Stephen (15 March 2010). "Aerojet confirms Russian engine is ready for duty". Spaceflight Now. Archived from the original on 13 August 2013. Retrieved 18 March 2010.
  20. ^ Bill Chappell (21 April 2013). "Antares Rocket Launch Is A Success, In Test Of Orbital Supply Vehicle". NPR.
  21. ^ Dan Leone (24 June 2013). "Orbital Sues ULA, Seeks RD-180 Engines, $515 Million in Damages". Space News. Archived from the original on 30 October 2013.
  22. ^ Amy Butler (24 June 2013). "Orbital Frustrated By Lack Of Antares Engine Options". Aviation Week and Space Technology. Archived from the original on 29 October 2013.
  23. ^ Clark, Stephen (1 November 2015). "Two Antares failure probes produce different results". Spaceflight Now. Retrieved 1 November 2015.
  24. ^ Morring, Frank Jr. (16 December 2014). "Antares Upgrade Will Use RD-181s In Direct Buy From Energomash". Aviation Week. Retrieved 28 December 2014.
  25. ^ "S.P.Korolev RSC Energia - LAUNCHERS". Energia. Archived from the original on 27 May 2008. Retrieved 15 January 2008.
  26. ^ "The Soyuz 1 (Soyuz 2-1v) Rocket". Russian Space Web. November 2010.
  27. ^ Zak, Anatoly. "The Soyuz-1 rocket". Russian Space Web. Retrieved 7 March 2010.
  28. ^ "NK-33 Engine Test Successful" (in Russian). Samara Today. 15 January 2013. Retrieved 3 March 2013.
  29. ^ "Kosmonavtika - par Nicolas Pillet".
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